Poly(ethylene oxide) based electrolytes are systems in which ionic salts are dissolved into an amorphous EO matrix. Potentials developed earlier to model crystalline and amorphous bulk PEO systems are here used for the MD simulation at 400 K of the behavi

Potentials developed earlier for crystalline and amorphous bulk PEO systems have been used for the MD simulation of a PEO surface model. The surface comprises the outer region of a 122 Angstrom-thick sheet of PEO in which the PEO, -(CH2-CH2-O)(n)- chains

The octakis(DMSO) (DMSO = dimethylsulfoxide) neodymium(III), samarium(III), gadolinium(III), dysprosium(III), erbium(III), and lutetium(III) iodides crystallize in the monoclinic space group P21/n (No. 14) with Z = 4, while the octakis(DMSO) iodides of the larger lanthanum(III), cerium(III), and praseodymium(III) ions crystallize in the orthorhombic space group Pbca (No. 61), Z = 8. In all [Ln(OS(Me2)8]I3 compounds the lanthanoid(III) ions coordinate eight DMSO oxygen atoms in a distorted square antiprism. Up to three of the DMSO ligands were found to be disordered and were described by two alternative configurations related by a twist around the metal−oxygen (Ln−O) bond. To resolve the atomic positions and achieve reliable Ln−O bond distances, complete semirigid DMSO molecules with restrained geometry and partial occupancy were refined for the alternative sites. This disorder model was also applied on previously collected data for the monoclinic octakis(DMSO)yttrium(III) iodide. At ambient temperature, the eight Ln−O bond distances are distributed over a range of about 0.1 Å. The average value increases from Ln−O 2.30, 2.34, 2.34, 2.36, 2.38, 2.40 to 2.43 Å (Ln = Lu, Er, Y, Dy, Gd, Sm, and Nd) for the monoclinic [Ln(OSMe2)8]I3 structures, and from 2.44, 2.47 to 2.49 Å (Ln = Pr, Ce, and La) for the orthorhombic structures, respectively. The average of the La−O and Nd−O bond distances remained unchanged at 100 K, 2.49 and 2.43 Å, respectively. Despite longer bond distances and larger Ln−O−S angles, the cell volumes are smaller for the orthorhombic structures (Ln = Pr, Ce, and La) than for the monoclinic structure with Ln = Nd, showing a more efficient packing arrangement. Raman and IR absorption spectra for the [Ln(OS(CH3)2)8]I3 (Ln = La, Ce, Pr, Nd, Gd, Tb, Dy, Er, Lu, and Y) compounds, also deuterated for La and Y, have been recorded and analyzed by means of normal coordinate methods. The force constants for the Ln−O and S−O stretching modes in the complexes increase with decreasing Ln−O bond distance and show increasing polarization of the bonds for the smaller and heavier lanthanoid(III) ions.

This thesis presents the synthesis, properties, and applications of two important classes of metal-organic frameworks (MOFs); lanthanide MOFs and hierarchical porous zeolitic imidazolate frameworks (ZIFs). The materials have been characterized using a wide range of techniques including diffraction, imaging, various spectroscopic techniques, gas sorption, dynamical light scattering (DLS) and thermogravimetric analysis (TGA).

In Chapter 1, the unique features of MOFs and ZIFs as well as their potential applications are summarized. In Chapter 2, different characterization techniques are presented.

Chapter 3 describes a family of new isoreticular lanthanide MOFs synthesized using tri-topic linkers of different sizes, H3L1-H3L4, denoted SUMOF-7I-IV (Ln) (SU; Stockholm University, Ln = La, Ce, Pr, Nd, Sm, Eu and Gd, Paper I). The SUMOF-7I-III (Ln) contain permanent pores and exhibit exceptionally high thermal and chemical stability. The luminescence properties of SUMOF-7IIs are reported (Paper II). The influences of Ln ions and the tri-topic linkers as well as solvent molecules on the luminescence properties are investigated. Furthermore, the potential of SUMOF-7II (La) for selective sensing of Fe (III) ions and the amino acid tryptophan is demonstrated (Paper III).

Chapter 4 presents a simple, fast and scalable approach for the synthesis of hierarchical porous zeolitic imidazolate framework ZIF-8 and ZIF-67 using triethylamine (TEA)-assisted approach (Paper IV). Organic dye molecules and proteins are encapsulated directly into the ZIFs using the one-pot method. The photophysical properties of the dyes are improved through the encapsulation into ZIF-8 nanoparticles (Paper IV). The porosity and surface area of the ZIF materials can be tuned using the different amounts of dye or TEA. To further simplify the synthesis of hierarchical porous ZIF-8, a template-free approach is presented using sodium hydroxide, which at low concentrations induces the formation of zinc hydroxide nitrate nanosheets that serve as in situ sacrificial templates (Chapter 5, Paper V). A 2D leaf-like ZIF (ZIF-L) is also obtained using the method. The hierarchical porous ZIF-8 and ZIF-L show good performance for CO2 sorption.

A trimethylamine (TEA)-assisted synthesis approach that combines the preparation of hierarchical porous zeolitic imidazolate framework ZIF-8 nanoparticles and one-pot encapsulation of target molecules is presented. Two dye molecules, rhodamine B (RhB) and methylene blue (MB), and one protein (bovine serum albumin, BSA) were tested as the target molecules. The addition of TEA into the solution of zinc nitrate promoted the formation of ZnO nanocrystals, which rapidly transformed to ZIF-8 nanoparticles after the addition of the linker 2-methylimidazole (Hmim). Hierarchical porous dye@ZIF-8 nanoparticles with high crystallinity, large BET surface areas (1300–2500 m2/g), and large pore volumes (0.5–1.0 cm3/g) could be synthesized. The synthesis procedure was fast (down to 2 min) and scalable. The Hmim/Zn ratio could be greatly reduced (down to 2:1) compared to previously reported ones. The surface areas, and the mesopore size, structure, and density could be modified by changing the TEA or dye concentrations, or by postsynthetic treatment using reflux in methanol. This synthesis and one-pot encapsulation approach is simple and can be readily scaled up. The photophysical properties such as lifetime and photostability of the dyes could be tuned via encapsulation. The lifetimes of the encapsulated dyes were increased by 3–27-fold for RhB@ZIF-8 and by 20-fold for MB@ZIF-8, compared to those of the corresponding free dyes. The synthesis approach is general, which was successfully applied for encapsulation of protein BSA. It could also be extended for the synthesis of hierarchical porous cobalt-based ZIF (dye@ZIF-67).

Two Ru( II) complexes, [ Ru( bpy) L-2]( ClO4) 2 ( 1) and [ Ru( bpy)(2)L']( BF4) 2 ( 2), where bpy is 2,2'-bipyridine, L is diacetyl dihydrazone, and L' 1: 2 is the condensate of L and acetone, are synthesized. From X-ray crystal structures, both are found to contain distorted octahedral RuN62+ cores. NMR spectra show that the cations in 1 and 2 possess a C-2 axis in solution. They display the expected metal-to-ligand charge transfer ( (MLCT)-M-1) band in the 400 - 500 nm region. Complex 1 is nonemissive at room temperature in solution as well as at 80 K. In contrast, complex 2 gives rise to an appreciable emission upon excitation at 440 nm. The room-temperature emission is centered at 730 nm ( lambda(max)(em)) with a quantum yield ( em) of 0.002 and a lifetime ( tau(em)) of 42 ns in an air-equilibrated methanol - ethanol solution. At 80 K, Phi(em) = 0.007 and tau(em)= 178 ns, with a lambda(max)(em) of 690 nm, which is close to the 0 - 0 transition, indicating an (MLCT)-M-3 excited-state energy of 1.80 eV. The radiative rate constant ( 5 x 10(4) s(-1)) at room temperature and 80 K is almost temperature independent. From spectroelectrochemistry, it is found that bpy is easiest to reduce in 2 and that L is easiest in 1. The implications of this are that in 2 the lowest (MLCT)-M-3 state is localized on a bpy ligand and in 1 it is localized on L. Transient absorption results also support these assignments. As a consequence, even though 2 shows a fairly strong and long-lived emission from a Ru( II) -> bpy CT state, the Ru( II) -> L CT state in 1 shows no detectable emission even at 80 K.

The structural effect on the metal-to-ligand charge transfer (MLCT) excited-state lifetime has been investigated in bis-tridentate Ru(II)-polypyridyl complexes based on the terpyridine-like ligands [6-(2,2'-bipyridyl)](2-pyridyl)methane (1) and 2-[6-(2,2'-bipyridyl)]-2-(2-pyridyl)propane (2). A homoleptic ([Ru(2)(2)](2+)) and a heteroleptic complex ([Ru(ttpy)(2)](2+)) based on the new ligand 2 have been prepared and their photophysical and structural properties studied experimentally and theoretically and compared to the results for the previously reported [Ru(1)(2)](2+). The excited-state lifetime of the homoleptic Ru-II complex with the isopropylene-bridged ligand 2 was found to be 50 times shorter than that of the corresponding homoleptic Ru-II complex of ligand 1, containing a methylene bridge. A comparison of the ground-state geometries of the two homoleptic complexes shows that steric interactions involving the isopropylene bridges make the coordination to the central Ru-II ion less octahedral in [Ru(2)(2)](2+) than in [Ru(1)(2))(2+). Calculations indicate that the structural differences in these complexes influence their ligand field splittings as well as the relative stabilities of the triplet metal-to-ligand charge transfer ((MLCT)-M-3) and metal-centered ((MC)-M-3) excited states. The large difference in measured excited-state lifetimes for the two homoleptic Ru-II complexes is attributed to a strong influence of steric interactions on the ligand field strength, which in turn affects the activation barriers for thermal conversion from (MLCT)-M-3 states to short-lived (MC)-M-3 states.

Ab initio electronic structure theory is known as a useful tool for prediction of materials properties. However, majority of simulations still deal with calculations in the framework of density functional theory with local or semi-local functionals carried out at zero temperature. We present new methodological solution.s, which go beyond this approach and explicitly take finite temperature, magnetic, and many-body effects into account. Considering Ti-based alloys, we discuss !imitations of the quasiharmonic approximation for the treatment of lattice vibrations, and present an accurate and easily extendable method to calculate free ,energies of strongly anharmonic solids. We underline the necessity to going beyond the state-of-the-art techniques for the determination of effective cluster interactions in systems exhibiting mctal-to-insulator transition, and describe a unified cluster expansion approach developed for this class of materials. Finally, we outline a first-principles method, disordered local moments molecular dynamics, for calculations of thermodynamic properties of magnetic alloys, like Cr1-x,.AlxN, in their high-temperature paramagnetic state. Our results unambiguously demonstrate importance of finite temperature effects in theoretical calculations ofthermodynamic properties ofmaterials.

Abstract Oxidative polymerization for the manufacture of conducting polymers such as poly(3,4-ethylenedioxy-thiophene) has traditionally employed iron(III) salts. Demonstrated in this study is vapour phase polymerization of 3,4-ethylenedio- xythiophene using a metal-free oxidant, ammonium persulfate, leading to films with an estimated conductivity of 75 S/cm. Additionally, a route for embedding active transition metal complexes into these poly(3,4-ethylenedioxythiophene)/-poly(styrene-4-sulfonate) (PEDOT/PSS) films via vapour assisted complexation is outlined. Here, the vapour pressure of solid ligands around their melting temperatures was exploited to ensure complexation to metal ions added into the oxidant mixture prior to polymerization of PEDOT. Four composite systems are discussed, viz. PEDOT/PSS embedded with tris(8-hydroxyquinolinato)cobalt(III), tris(2,2-bipyridine)cobalt(II), tris(1,10- phenanthroline)cobalt(II) and tris(8-hyd-roxyquinolinato)aluminium(III). Using these composites, electrochemical reduction of nitrite to ammonia with a faradaic efficiency of 61% was reported.

The rates and activation parameters of water exchange at pH 3.0 have been determined using variable temperature 17O NMR spectroscopy for four CoII complexes and one MnII complex: [Co(bpy)(H2O)4]2+, [Co(bpy)2 (H2O)2]2+, [Co(phen)-(H2O)4]2+, [Co(phen)2 (H2O)2]2+, and [Mn(bpy)(H2O)4]2+ (bpy = 2,2′-bipyridyl and phen = 1,10-phenanthroline). Substitution of aquo ligands with 1,10-phenanthroline or 2,2′-bipyridyl leads to an increase in the rate of exchange in the manganese complexes, from k298 (1.8 ± 0.1) × 107 s-1 for [Mn(H2O)6]2+ to (7.2 ± 0.3) × 107 s-1 for [Mn(phen)2 (H2O)2]2+, whereas the trends are more complex for the cobalt complexes. We have used the new data in conjunction with literature data for similar complexes to analyse the effect of M–OH2 distance and degree of substitution.

In the preparation of bioactive composites containing hydroxyapatite, Ca5(PO4)3(OH), and an oxide it has been a problem to prevent the hydroxyapatite from decomposing in the sintering process. This is because H2O is evolved when hydroxyapatite is heated, implying that the occupied OH- positions in hydroxyapatite structure are partly replaced by vacancies and O2- ions. The thermal stability of hydroxyapatite was found to depend on the fraction of vacancies and O2- ions present. The decomposition of the hydroxyapatite is initiated when a critical fraction of the OH- ions has been lost, and it is not specifically related to the temperature applied or atmosphere used. The decomposition temperature of hydroxyapatite and fluoride-containing apatite, Ca5(PO4)3(OH)1-xFx, in the presence of alumina has been studied and found to increase with increasing x value in Ca5(PO4)3(OH)1-xFx. By combining this observation with thermogravimetric studies of hydroxyapatite and Ca5(PO4)3OH1-xFxsamples, it was concluded that the decomposition of hydroxyapatite in the presence of alumina can be described by the following reactions:

Ca5(PO4)3(OH) --> Ca5(PO4)3(OH)1-xOx/2 + x/2 H20

2 Ca5(PO4)3(OH)1-xOx/2+ Al2O3 --> 3 Ca3(PO4)2 + CaAl2O4 + (1-x) H2O

With the use of a closed system for sintering the aluminañapatite composites, the loss of water can be reduced. The equilibrium in the first reaction will then be shifted to the left, and the second reaction will not occur. This implies that a higher sintering temperature can be used to densify an aluminañhydroxyapatite composite. Accordingly, composites of alumina and zirconia, respectively, with hydroxyapatite could be hot isostatically pressed (HIPed) in a closed system at 1200oC and at a pressure of 160 MPa without any detectable decomposition of the hydroxyapatite. Another way to avoid excess formation of vacancies is to replace some of the OH-ions with F-. This implies that the equilibrium in the first reaction given above is shifted to the left, thus improving the thermal stability of the apatite.

The main result of this thesis work is a more detailed understanding of the reaction between the oxide and hydroxyapatite, which has made it possible to prepare densified oxide-hydroxyapatite composites without decomposition of the hydroxyapatite phase.

Perovskite Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) is synthesized via a chemical co-precipitation technique for a low temperature solid oxide fuel cell (LTSOFC) (300-600 degrees C) and electrolyte-layer free fuel cell (EFFC) in a comprehensive study. The EFFC with a homogeneous mixture of samarium doped ceria (SDC): BSCF (60%:40% by weight) which is rather similar to the cathode (SDC: BSCF in 50%:50% by weight) used for a three layer SOFC demonstrates peak power densities up to 655 mW/cm(2), while a three layer (anode/ electrolyte/cathode) SOFC has reached only 425 mW/cm(2) at 550 degrees C. Chemical phase, crystal structure and morphology of the as-prepared sample are characterized by X-ray diffraction and field emission scanning electron microscopy coupled with energy dispersive spectroscopy. The electrochemical performances of 3-layer SOFC and EFFC are studied by electrochemical impedance spectroscopy (EIS). As-prepared BSCF has exhibited a maximum conductivity above 300 S/cm at 550 degrees C. High performance of the EFFC device corresponds to a balanced combination between ionic and electronic (holes) conduction characteristic. The Schottky barrier prevents the EFFC from the electronic short circuiting problem which also enhances power output. The results provide a new way to produce highly effective cathode materials for LTSOFC and semiconductor designs for EFFC functions using a semiconducting-ionic material.

The diamagnetic complexes [Ru(tpm)(bqdi)(Cl)]ClO4 ([1]ClO4) (tpm = tris(1-pyrazolyl)methane, bqdi =o-benzoquinonediimine) and [Ru(tpm)(bqdi)(H2O)](ClO4)2 ([2](ClO4)2) have been synthesized. Thevalence state-sensitive bond distances of coordinated bqdi [C–N: 1.311(5)/1.322(5) Å in [1]ClO4;1.316(7)/1.314(7) Å in molecule A and 1.315(6)/1.299(7) Å in molecule B of [2](ClO4)2] imply its fullyoxidised quinonediimine (bqdi0) character. DFT calculations of 1+ confirm the {RuII–bqdi0} versus the antiferromagneticallycoupled {RuIII–bqdi˙−} alternative. The 1H NMR spectra of [1]ClO4 in different solventsshow variations in chemical shift positions of the NH (bqdi) and CH (tpm) proton resonances due to theirdifferent degrees of acidity in different solvents. In CH3CN/0.1 mol dm−3 Et4NClO4, [1]ClO4 undergoesone reversible RuII ⇌ RuIII oxidation and two reductions, the reversible first electron uptake being bqdibased (bqdi0/bqdi˙−). The electrogenerated paramagnetic species {RuIII–bqdi0}(12+) and {RuII–Q˙−}(1)exhibit RuIII-type (12+: <g> = 2.211/Δg = 0.580) and radical-type (1: g = 1.988) EPR signals, respectively, asis confirmed by calculated spin densities (Ru: 0.767 in 12+, bqdi: 0.857 in 1). The aqua complex [2](ClO4)2exhibits two one-electron oxidations at pH = 7, suggesting the formation of {RuIVvO} species. The electronicspectral features of 1n (n = charge associated with the different redox states of the chloro complex:2+, 1+, 0) in CH3CN and of 22+ in H2O have been interpreted based on the TD-DFT calculations. The applicationpotential of the aqua complex 22+ as a pre-catalyst towards the epoxidation of olefins has beenexplored in the presence of the sacrificial oxidant PhI(OAc)2 in CH2Cl2 at 298 K, showing the desiredselectivity with a wide variety of alkenes. DFT calculations based on styrene as the model substratepredict that the epoxidation reaction proceeds through a concerted transition state pathway.IntroductionThe well recognized mixing of ruthenium dπ orbitals andπ orbitals of redox non-innocent quinonoid moieties introducesseveral manifestations with respect to the valence distributionat the metal–quinonoid interface, as depicted in Scheme 1.1This makes the electronic structure of such complexes sensitiveto the molecular frameworks, and in many occasions theexperimental results

The article deals with the newly designed mononuclear and asymmetric dinuclear osmium(II) complexesOsII(bpy)2(HL2−) (1) and [(bpy)2OsII(μ-HL2−)OsII(bpy)2](Cl)2 ([2](Cl)2)/[(bpy)2OsII(μ-HL2−)OsII(bpy)2](ClO4)2([2](ClO4)2), respectively, (H3L = 5-(1H-benzo[d]imidazol-2-yl)-1H-imidazole-4-carboxylic acid and bpy = 2,2’-bipyridine). The identity of 1 has been established by its single crystal X-ray structure. The ligand (HL2−)-basedprimary oxidation process (E°298, 0.23 V versus SCE) along with the partial metal contribution (∼20%) in 1 hasbeen revealed by the ligand-dominated HOMO of 1 (HL2−: 88%, Os: 8%), as well as by the Mulliken spindensity distribution of 1+ (HL2−: 0.878, Os: 0.220). Accordingly, 1+ exhibits a free radical type EPR at 77 K witha partial metal-based anisotropic feature (g1 = 2.127, g2 = 2.096, g3 = 2.046; <g> = 2.089; Δg = 0.08).1H-NMR of the dinuclear 22+ in CDCl3 suggests an intimate mixture of two diastereomeric forms in a 1 : 1ratio. The DFT-supported predominantly Os(II)/Os(III)-based couples of asymmetric 22+ at 0.24 V and 0.50 Vversus SCE result in a comproportionation constant (Kc) value of 8.2 × 104. The class I mixed valent state of23+ (S = 1/2) has, however, been corroborated by the Mulliken spin density distribution of Os1: 0.887, Os2:0.005, HL2−: 0.117, as well as by the absence of a low-energy IVCT (intervalence charge transfer) band in thenear-IR region (up to 2000 nm). The appreciable spin accumulation on the bridge in 23+ or 24+ (S = 1, Os1:0.915, Os2: 0.811 and HL2−: 0.275) implies a mixed electronic structural form of [(bpy)2OsIII(μ-HL2−)-OsII(bpy)2]3+(major)/[(bpy)2OsII(μ-HL•−)OsII(bpy)2]3+(minor) or [(bpy)2OsIII(μ-HL2−)OsIII(bpy)2]4+(major)/[(bpy)2-OsIII(μ-HL•−)OsII(bpy)2]4+ (minor), respectively. The mixed valent {OsIII(μ-HL2−)OsII} state in 23+, however, fails toshow EPR at 77 K due to the rapid spin relaxation process. The DFT-supported bpy-based two reductions forboth 1+ and 22+ appear in the potential range of −1.5 V to −1.8 V versus SCE. The electronic transitions in 1nand 2n are assigned by the TD-DFT calculations. Furthermore, the potential anion sensing features of 1 and22+ via the involvement of the available N–H proton in the framework of coordinated HL2− have been evaluatedby different experimental investigations, in conjunction with the DFT calculations, using a wide variety ofanions such as F−, Cl−, Br−, I−, OAc−, SCN−, HSO4− and H2PO4−. This, however, establishes that both 1 and 22+are equally efficient in recognising the F− ion selectively, with log K values of 6.83 and 5.89, respectively.

The compounds [(acac)2RuIII(μ-H2L2−)RuIII(acac)2] (rac, 1, and meso, 1′) and[(bpy)2RuII(μ-H2L•−)RuII(bpy)2](ClO4)3 (meso, [2](ClO4)3) have been structurally, magnetically,spectroelectrochemically, and computationally characterized (acac− = acetylacetonate, bpy= 2,2′-bipyridine, and H4L = 1,4-diamino-9,10-anthraquinone). The N,O;N′,O′-coordinated μ-H2Ln− forms two β-ketiminato-type chelate rings, and 1 or 1′ are connected via NH···Ohydrogen bridges in the crystals. 1 exhibits a complex magnetic behavior, while [2](ClO4)3 is aradical species with mixed ligand/metal-based spin. The combination of redox noninnocentbridge (H2L0 → → → →H2L4−) and {(acac)2RuII} → →{(acac)2RuIV} or {(bpy)2RuII} →{(bpy)2RuIII} in 1/1′ or 2 generates alternatives regarding the oxidation state formulations for the accessible redox states (1n and2n), which have been assessed by UV−vis−NIR, EPR, and DFT/TD-DFT calculations. The experimental and theoretical studiessuggest variable mixing of the frontier orbitals of the metals and the bridge, leading to the following most appropriate oxidationstate combinations: [(acac)2RuIII(μ-H2L•−)RuIII(acac)2]+ (1+) → [(acac)2RuIII(μ-H2L2−)RuIII(acac)2] (1) → [(acac)2RuIII(μ-H2L•3−)RuIII(acac)2]−/[(acac)2RuIII(μ-H2L2−)RuII(acac)2]− (1−) → [(acac)2RuIII(μ-H2L4−)RuIII(acac)2]2−/[(acac)2RuII(μ-H2L2−)RuII(acac)2]2− (12−) and [(bpy)2RuIII(μ-H2L•−)RuII(bpy)2]4+ (24+) → [(bpy)2RuII(μ-H2L•−)RuII(bpy)2]3+/[(bpy)2RuII(μ-H2L2−)RuIII(bpy)2]3+ (23+) → [(bpy)2RuII(μ-H2L2−)RuII(bpy)2]2+ (22+). The favoring of RuIII by σ-donatingacac− and of RuII by the π-accepting bpy coligands shifts the conceivable valence alternatives accordingly. Similarly, theintroduction of the NH donor function in H2Ln as compared to O causes a cathodic shift of redox potentials with correspondingconsequences for the valence structure.

Two novel trans-A2B-corroles and three[(corrolato){FeNO}6] complexes have been prepared andcharacterized by various spectroscopic techniques. In thenative state, all these [(corrolato){FeNO}6] species arediamagnetic and display “normal” chemical shifts in the 1HNMR spectra. For two of the structurally characterized[(corrolato){FeNO}6] derivatives, the Fe−N−O bond anglesare 175.0(4)° and 171.70(3)° (DFT: 179.94°), respectively,and are designated as linear nitrosyls. The Fe−N (NO) bonddistances are 1.656(4) Å and 1.650(3) Å (DFT: 1.597 Å),which point toward a significant FeIII → NO back bonding.The NO bond lengths are 1.159(5) Å and 1.162(3) Å (DFT:1.162 Å) and depict their elongated character. These structural data are typical for low-spin Fe(III). Electrochemicalmeasurements show the presence of a one-electron oxidation and a one-electron reduction process for all the complexes. Theone-electron oxidized species of a representative [(corrolato){FeNO}6] complex exhibits ligand to ligand charge transfer(LLCT) transitions (cor(π) → cor(π*)) at 399 and 637 nm, and the one-electron reduced species shows metal to ligand chargetransfer (MLCT) transition (Fe(dπ) → cor(π*)) in the UV region at 330 nm. The shift of the νNO stretching frequency of arepresentative [(corrolato){FeNO}6] complex on one-electron oxidation occurs from 1782 cm−1 to 1820 cm−1, whichcorresponds to 38 cm−1, and on one-electron reduction occurs from 1782 cm−1 to 1605 cm−1, which corresponds to 177 cm−1.The X-band electron paramagnetic resonance (EPR) spectrum of one-electron oxidation at 295 K in CH2Cl2/0.1 M Bu4NPF6displays an isotropic signal centered at g = 2.005 with a peak-to-peak separation of about 15 G. The in situ generated oneelectronreduced species in CH2Cl2/0.1 M Bu4NPF6 at 295 K shows an isotropic signal centered at g = 2.029. The 99%contribution of corrole to the HOMO of native species indicates that oxidation occurs from the corrole moiety. The results of theelectrochemical and spectroelectrochemical measurements and density functional theory calculations clearly display a preferenceof the {FeNO}6 unit to get reduced during the reduction step and the corrolato unit to get oxidized during the anodic process.Comparisons are presented with the structural, electrochemical, and spectroelectrochemical data of related compounds reportedin the literature, with a particular focus on the interpretation of the EPR spectrum of the one-electron oxidized form.

ZSM-5 is an aluminosilicate zeolite with high Si/Al ratio with suitable properties for catalysis, ion exchange, adsorption and membrane applications. The main goal of this thesis was to study the growth of ZSM-5 zeolite crystals from inexpensive natural sources of silica and alumina, as well as n-butylamine (NBA) as a low-cost structure directing agent.

The first objective of this work was to develop pathways to synthesize ZSM-5 crystals from kaolin clay or diatomaceous earth, two inexpensive natural sources of silica and alumina (Paper I). In the case of kaolin, a heat treatment was used in order to form amorphous metakaolinite. Subsequently, dealumination of the raw materials by acid leaching made it possible to reach appropriate Si/Al ratios and to reduce the amount of impurities. Finally, leached metakaolinite or diatomaceous earth was reacted with sodium hydroxide and NBA. After synthesis optimization, both sources of aluminosilicates were found to behave differently during the course of synthesis and to lead to slightly different reaction products. The final products exhibited Si/Al ratios in the range 10-20. The use of leached diatomaceous earth allowed to reach higher yield of ZSM-5 crystals within comparable synthesis times. However, low amounts of mordenite were inevitably formed as a by-product, which was related to the high calcium content of diatomaceous earth. Therefore, the rest of the thesis focused on the kaolin system.

In order to study the growth mechanism of ZSM-5 from leached metakaolinite, a proper methodology to gain local compositional data by energy dispersive spectroscopy (EDS) on aluminosilicates was developed (Paper II). Zeolite A was used as a model system that could be ion-exchanged with various elements. In order to evaluate the reliability of the measurements, inductively coupled plasma-sector field mass spectrometry (ICP-SFMS) and EDS were compared. The EDS method developed in this work resulted in molar ratios very close to theoretical values and was therefore found more reliable than ICP-SFMS. Therefore, the method developed for zeolite A was applied in the rest of the thesis work to study the formation and growth of ZSM-5 crystals.

The second part of this work focused on the kaolin system in order to understand the nucleation and growth processes of the ZSM-5 crystals. This system was heterogeneous, due to the formation of a gel upon heating of the synthesis mixture. First, the internal structure of the gel was investigated (Paper III). Second, a kinetic study was performed and compared with microstructural observations (Paper IV). Finally, the mechanisms leading to Al-zoning and dendritical growth of the zeolite crystals were investigated (Paper V). The characterization of the intermediate phases during the different stages of the hydrothermal synthesis were analyzed by different analytical techniques, such as inductively coupled plasma-sector field mass spectrometry (ICP-SFMS), dynamic light scattering (DLS), extreme high resolution-scanning electron microscopy (XHR-SEM), energy dispersive spectroscopy (EDS), high resolution-transmission electron microscopy (HR-TEM), X-ray diffraction (XRD) and nitrogen gas adsorption.

These investigations led to several important conclusions: 1) The walls of the gel were shown for the first time to be inhomogeneous and to possess a biphasic internal structure consisting of a mesoporous skeleton of aluminosilicate nanoparticles embedded in a silicate-rich soluble matrix of soft matter. 2) The kinetic study and microstructural evidences indicated that the early crystals were fully embedded inside the gel phase and that crystal growth was retarded, as the formation of the gel occurred simultaneously with the early growth of the crystals. Hence, nucleation and growth appeared to be solution mediated. 3) Finally, the Al zoning of the crystals was related to the biphasic internal structure of the gel, since the silicate-rich matrix was preferentially consumed first. 4) The dendrites present at the surface of the crystals during most of the growth process were shown to be caused by the presence of a web of nanoparticles, most likely originating from the mesoporous skeleton inside the gel.

In the future, these findings are expected to lead to optimized synthesis pathways of catalysts with homogeneous properties and to contribute to the development of poor regions in Bolivia.

The mechanism for hydrogenation of dimethylmaleate in water using cationic rhodium complexes with water-soluble bi-dentate phosphines has been investigated using kinetics and a novel method for the indirect detection of intermediates in catalytic hydrogenation reactions, whereby a late intermediate was detected. A mechanism is proposed involving fast, irreversible substrate binding followed by a rate-determining reaction with dihydrogen.

A route for the synthesis of TiC, TiCyN1-y, TaxTi1-xC and TaxTi1-xCyN1-y whiskers via a carbothermal Vapour-Liquid-Solid (VLS) growth mechanism, yielding 70-90 vol.% whiskers, has been established. The whiskers were uniform in diameter (0.3-0.6mm), and had a length of about 10-30mm. The starting materials consisted of TiO2 and/or Ta2O5, C, a catalyst metal (Ni or Fe) and NaCl. Carbon was added to reduce the oxides, and NaCl to provide chlorine in the formation of TiClx(g) and TaOxCly(g) species. The overall chemical reaction is a straightforward carbothermal reduction process. The optimum synthesis temperature was found to be 1250°C for TiCyN1-y, TaxTi1-xC and TaxTi1-xCyN1-y whisker, and 1400°C for TiC. The growth direction of the whiskers was found to be <100> for TaC and TaxTi1-xC and either <100> or <111> for TiC. Nitridation of TiC whiskers yielded TiCyN1-y whiskers with morphology and chemical composition different from those obtained by the carbothermal VLS growth mechanism. From oxidation studies it was found that TiC had the lowest oxidation resistance (onset temperature Ton=390°C) and that TaC had the highest (Ton=550°C). The oxidation onset temperature was found to increase with increasing x-value for both TaxTi1-xC and TaxTi1-xCyN1-y whiskers. Microscopy studies (SEM and TEM) showed that whiskers with a native diameter exceeding 0.3 mm split into two halves along their length when oxidised. It was found that the TiO2 particle size of oxidised TaxTi1-xC whiskers are markedly smaller than that obtained from oxidation of TiC whiskers, whereas the Ta2O5 particle size was the same as that observed for oxidised TaC whiskers.

32.

Ahvenniemi, Esko

et al.

Aalto University, Finland.

Akbashev, Andrew R.

Stanford University, CA 94305 USA.

Ali, Saima

Aalto University, Finland.

Bechelany, Mikhael

University of Montpellier, France.

Berdova, Maria

University of Twente, Netherlands.

Boyadjiev, Stefan

Bulgarian Academic Science, Bulgaria.

Cameron, David C.

Masaryk University, Czech Republic.

Chen, Rong

Huazhong University of Science and Technology, Peoples R China.

Chubarov, Mikhail

University of Grenoble Alpes, France.

Cremers, Veronique

University of Ghent, Belgium.

Devi, Anjana

Ruhr University of Bochum, Germany.

Drozd, Viktor

St Petersburg State University, Russia.

Elnikova, Liliya

Institute Theoret and Expt Phys, Russia.

Gottardi, Gloria

Fdn Bruno Kessler, Italy.

Grigoras, Kestutis

VTT Technical Research Centre Finland, Finland.

Hausmann, Dennis M.

Lam Research Corp, OR 97062 USA.

Seong Hwang, Cheol

Seoul National University, South Korea; Seoul National University, South Korea.

Atomic layer deposition (ALD), a gas-phase thin film deposition technique based on repeated, self-terminating gas-solid reactions, has become the method of choice in semiconductor manufacturing and many other technological areas for depositing thin conformal inorganic material layers for various applications. ALD has been discovered and developed independently, at least twice, under different names: atomic layer epitaxy (ALE) and molecular layering. ALE, dating back to 1974 in Finland, has been commonly known as the origin of ALD, while work done since the 1960s in the Soviet Union under the name "molecular layering" (and sometimes other names) has remained much less known. The virtual project on the history of ALD (VPHA) is a volunteer-based effort with open participation, set up to make the early days of ALD more transparent. In VPHA, started in July 2013, the target is to list, read and comment on all early ALD academic and patent literature up to 1986. VPHA has resulted in two essays and several presentations at international conferences. This paper, based on a poster presentation at the 16th International Conference on Atomic Layer Deposition in Dublin, Ireland, 2016, presents a recommended reading list of early ALD publications, created collectively by the VPHA participants through voting. The list contains 22 publications from Finland, Japan, Soviet Union, United Kingdom, and United States. Up to now, a balanced overview regarding the early history of ALD has been missing; the current list is an attempt to remedy this deficiency. (C) 2016 Author(s).

The thermoelectric (TE) phenomena are intensively explored by the scientific community due to the rather inefficient way energy resources are used with a large fraction of energy wasted in the form of heat. Among various materials, mixed ion-electron conductors (MIEC) are recently being explored as potential thermoelectrics, primarily due to their low thermal conductivity. The combination of electronic and ionic charge carriers in those inorganic or organic materials leads to complex evolution of the thermovoltage (Voc) with time, temperature, and/or humidity. One of the most promising organic thermoelectric materials, poly(3,4-ethyelenedioxythiophene)-polystyrene sulfonate (PEDOT-PSS), is an MIEC. A previous study reveals that at high humidity, PEDOT-PSS undergoes an ionic Seebeck effect due to mobile protons. Yet, this phenomenon is not well understood. In this work, the time dependence of the Voc is studied and its behavior from the contribution of both charge carriers (holes and protons) is explained. The presence of a complex reorganization of the charge carriers promoting an internal electrochemical reaction within the polymer film is identified. Interestingly, it is demonstrated that the time dependence behavior of Voc is a way to distinguish between three classes of polymeric materials: electronic conductor, ionic conductor, and mixed ionic–electronic conductor

Adsorbents with high surface area are potential candidates forefficient postcombustion CO2 capture. Binderless zeolite 13Xmonoliths with a hierarchical porosity and high CO2 uptakehave been produced by slip casting followed by pressurelessthermal treatment. The zeolite powder displayed an isoelectricpoint at pH 4.7 and electrostatically stabilized suspensions couldbe prepared at alkaline pH. The volume fraction-dependentsteady shear viscosity could be fitted to a modified Krieger–Dougherty model with a maximum volume fraction of 0.66. Thenarrow temperature range where monoliths could be producedwithout significant loss of the microporous surface area wasidentified and related to the phase behavior of the 13X material.Slip casting of concentrated suspensions followed by thermaltreatment of the powder bodies at a temperature of 8001Cwithout holding time resulted into strong hierarchically porouszeolite 13X monolith that displayed a CO2 uptake larger than29 wt%.

Diatomite powder, a naturally occurring porous raw material, was used to fabricate ceramic materials withbimodal porosity and high strength. The effect of the sintering temperature on the density and porosity ofdry pressed diatomite green bodies was evaluated using mercury porosimetry and water immersionmeasurements. It was found that the intrinsic porosity of the diatomite particles with a pore size around0.2 μm was lost at sintering temperatures above 1200 °C. Maintaining the sintering temperature at around1000 °C resulted in highly porous materials that also displayed a high compressive strength. Microstructuralstudies by scanning electron microscopy and energy-dispersive X-ray analysis suggested that the porecollapse was facilitated by the presence of low melting impurities like Na2O and K2O.

We have deposited Ti–Si–C thin films using high-power impulse magnetron sputtering (HIPIMS) from a Ti3SiC2 compound target. The as-deposited films were composite materials with TiC as the main crystalline constituent. X-ray diffraction and photoelectron spectroscopy indicated that they also contained amorphous SiC, and for films deposited on inclined substrates, crystalline Ti5Si3Cx. The film morphology was dense and flat, while films deposited with direct-current magnetron sputtering under comparable conditions were rough and porous. We show that, due to the high degree of ionization of the sputtered species obtained in HIPIMS, the film composition, in particular the C content, depends on substrate inclination angle and Ar process pressure.

Hydroxyapatite constitutes the main inorganic part of the skeleton, and since the beginning of the seventies, synthetic apatite has been used in implants. The physical properties of this crystalline material are directly dependent on its atomic arrangement. If a better understanding of apatite chemistry is sought, important for e.g. the development of new implant materials, it is absolutely crucial to know the detailed structural chemistry of the apatites. It is in this context that this thesis fits.

X-ray and electron diffraction techniques in combination with high resolution transmission electron microscopy have been used for the characterisation of the new compounds and the combination of these techniques has been particularly useful.

Common for the studies presented is that they focus on the anion ordering along the hexagonal axis within the apatite framework, this being responsible for the new structures discovered:

The crystal structure of completely dehydrated hydroxyapatite, oxyapatite, has been elucidated from HREM images.

Partially dehydrated hydroxyapatite is shown to be triclinic.

The sulfo- and seleno analogues of oxyapatite have been prepared and their structures refined from X-ray diffraction data.

A new commensurate modulation along c is found for iodo-oxyapatite.

A new incommensurate modulation along c is found for cadmium-bromoapatite.

As a consequence of the structural chemical investigations performed, the hypothesis arose that it might be possible to manipulate the hydroxide ion ordering in hydroxyapatite achieving a piezoelectric apatite. This hypothesis has recently been confirmed. This new apatite may find important applications in the development of new, biocompatible, implant materials.

The flow in a narrow (3 mm wide) vertical gap of an electrochemical cell with gas evolution at one electrode is modeled by means of the two-phase Euler-Euler model. The results indicate that at certain conditions an unsteady type of flow with vortices and recirculation regions can occur. Such flow pattern has been observed experimentally, but not reported in previous modeling studies. Further analysis establishes that the presence of a sufficient amount of small (similar to 10 mu m) bubbles is the main factor causing this type of flow at high current densities.

Periodic ab initio calculations of the O-17 and H-2 quadrupole coupling constants (QCC) and their shifts have been performed for ice VIII and ice IX. Cluster calculations were done for smaller water clusters and chains. The ice Vm crystal structure was op

A number of hydrogen-bond related quantities-geometries, interaction energies, dipole moments, dipole moment derivatives, and harmonic vibrational frequencies-were calculated at the Hartree-Fock, MP2, and different DFT levels for the HCN dimer and the pe

A number of hydrogen-bond related quantities-geometries, interaction energies, dipole moments, dipole moment derivatives, and harmonic vibrational frequencies-were calculated at the Hartree-Fock, MP2, and different DFT levels for the HCN dimer and the pe

A highly-sensitive glucose biosensor amenable to ultraminiaturisation was fabricated by immobilization of glucose oxidase (wGOX), onto a poly(2,6-diaminopyridine)/multi-walled carbon nanotube/glassy carbon electrode (poly(2,6-DP)/MWCNT/GCE). Cyclic voltammetry was used for both the electrochemical synthesis of poly-(2,6-DP) on the surface of a MWCNT-modified GC electrode, and characterization of the polymers deposited on the GC electrode. The synergistic effect of the high active surface area of both the conducting-polymer, i.e., poly-(2,6-DP) and MWCNT gave rise to a remarkable improvement in the electrocatalytic properties of the biosensor. The transfer coefficient (alpha), heterogeneous electron transfer rate constant and Michaelis-Menten constant were calculated to be 0.6, 4 s-1 and 0.22 mM at pH 7.4, respectively. The GOx/poly(2,6-DP)/MWCNT/GC bioelectrode exhibited two linear responses to glucose in the concentration ranging from 0.42 mu M to 8.0 mM with a correlation coefficient of 0.95, sensitivity of 52.0 mu AmM-1 cm-2, repeatability of 1.6% and long-term stability, which could make it a promising bioelectrode for precise detection of glucose in the biological samples. (C) 2016 Elsevier B.V. All rights reserved.

There is an increasing demand for glass materials with better mechanical and optical properties for display and electronic applications. This paper describes the deposition of novel thin films of Mg-Si-O-N onto float glass substrates. Amorphous thin films in the Mg-Si-O-N system with high nitrogen and magnesium contents were deposited by reactive RF magnetron co-sputtering from Mg and Si targets in Ar/N2/O2 gas mixtures. The thin films studied span an unprecedented range of compositions up to 45 at% Mg and 80 at% N out of cations and anions respectively. Thin films in the Mg-Si-O-N system were found to be homogeneous and transparent in the visible region. Mechanical properties like hardness (H) and reduced elastic modulus (Er) show high values, up to 21 GPa and 166 GPa respectively. The refractive index (1.87-2.00) increases with increasing magnesium and nitrogen contents.

There is an increasing demand for glass materials with better mechanical and optical properties for display and electronic applications. This paper describes the deposition of novel thin films of Mg-circle divide-Si-O-N onto float glass substrates. Amorphous thin films in the Mg-Si-O-N system with high nitrogen and magnesium contents were deposited by reactive RF magnetron co-sputtering from Mg and Si targets in Ar/N-2/O-2 gas mixtures. The thin films studied span an unprecedented range of compositions up to 45 at% Mg and 80 at% N out of cations and anions respectively. Thin films in the Mg-Si-O-N system were found to be homogeneous and transparent in the visible region. Mechanical properties like hardness (H) and reduced elastic modulus (Er) show high values, up to 21 GPa and 166 GPa respectively. The refractive index (1.87-2.00) increases with increasing magnesium and nitrogen contents. (C) 2016 Elsevier Ltd. All rights reserved.

The new quaternary layered oxide CoMo2Sb2O10 was synthesized by hydrothermal synthesis techniques, and its structure was determined from single-crystal X-ray diffraction data. CoMo2Sb2O10 crystallizes in the monoclinic space group C2/c with one Sb3+, Mo6+, and Co2+ atom site per unit cell, respectively. The crystal structure contains building units consisting of [Co2O8](n), [Mo2O8](n), and [SbO2](n) chains. These are connected through corner sharing to form charge neutral [CoMo2Sb2O10](n) layers. Thermal decomposition of CoMo2Sb2O10 starts at 550 degrees C. The magnetic susceptibility follows a Curie Weiss law above 50 K with a Curie constant of C = 3.46 emu K mol(-1) corresponding to an effective moment of mu(eff) = 5.26 mu(B) per cobalt atom and a Curie-Weiss temperature theta = -13.2 K. Short-range anti-ferromagnetic ordering dominates below 5 K. Magnetic susceptibility and heat capacity data can be successfully modeled by the predictions from an Ising linear chain with an intrachain spin exchange of ca. -7.8 K.

Tungsten oxide nanoparticles were generated by excimer (ArF) laser assisted chemical vapor deposition from WF6/H2/O2/Ar gas mixtures. The deposited particles were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy. The deposition rate as a function of the partial pressures of the reactants and of the laser fluence was measured by X-ray fluorescence spectroscopy. The mean diameter of the deposited tungsten oxide particles varied with the experimental parameters and was typically 23 nm. Particles with a higher degree of crystallinity were observed at a laser fluence exceeding 130 mJ/cm2, and X-ray amorphous particles were obtained below 110 mJ/cm2. The amorphous tungsten oxide had a stoichiometry ranging from WO2.7 to WO3. Deposits were formed only when hydrogen was present in the gas mixture.

Tris(trimethylsilyl)silyl-N,N-dimethylmethaneamide, herein named hypersilylamide, is a convenient and efficient source of the hypersilyl group in the first widely applicable acid catalyzed protocol for silyl group protection of primary, secondary, tertiary alkyl as well as aryl alcohols and thiols in high yields. The sole by-product is N,N-dimethylformamide (DMF) and a range of solvents can be used, including DMF. A high selectivity in the protection of diols can be achieved, also for diols with very small differences in the steric demands at the two hydroxyl groups. Moreover, in the protection of equivalent alcohol and thiol sites the protection of the alcohol is faster, allowing for selective protection in high yields. Quantum chemical calculations at the M062X hybrid meta density functional theory level give insights on the mechanism for the catalytic process. Finally, the hypersilyl group is easily removed from all protected alcohols and thiols examined herein by irradiation at 254 nm.